Hyundai Santa Fe problems....

The steam will clean the outside of the motor, think of it like wiping the glass on the tank. Using the SeaFoam in the vaccuum lines will help clear any debris that has built up on the inside and maybe be causing sensors to act up. This is more like the airline on your skimmer plugging up. Give it a cleaning and it's back to normal. lol. This very well could work and is cheap and easy. Def. worth a try before you start replacing expensive parts.

 

Simple things come to mind but start in this order will hopefully save money.
You have mileage that would call for and also at this point it won't hurt to look into,

1- get the alternator checked at autozone if it's starting to go it will cause this. The reasion I say this is your alternator might only be giving you electric when moving @ 10+ mpg at idle they don't produce much to began with and if its going you will experience these issue.
2- replace fuel filter cheap and easy also will cause a stalling effect at low rpm
3- when is the last time you had a tune up? Spark plugs and wires ? Might need one.
4- it could be you fuel pump this is what I would go for after the first 3 at 120k I'd say you got a lot out of it already.

you can have them check your tps but if it's out you should have a check engine light the above this I'm suggestion won't cause a check engine light with the exception of the alternator but generally it won't throw a light unless it's out and sometimes even at that it won't.

I am more then certain it Is not your tranny.

If you do the above with no sucsess there is a,good possibility it could be your timing belt as your mileage is at the point that they would recommend it to be replaced also.
Do not let them try and talk you into doing that right off the back ! if they try go to other mechanic as they are trying to take you... Also if it does turn out to be a timming issue please be sure to shop around and google reviews on shops... If a mechanic does it It incorrect your motor will go boom.... If you need any other help let me know.. I'm faily versed.
Sil

 

Do not replace the transmission. Check your mass oxygen sensor. It sounds to me the car is getting a rush of air when it is not needed which would = acceleration and vice versa when it is needed. It is difficult to say for sure without seeing it in person however, this is where I would start. Do you have a local car parts store that is helpful with amatuer mechanics?

 

I'll disagree with some things you stated and I put replys in there but can't figure the color out on my iPad
I have rebuilt a few motors and built a few rock buggies in my time but I'm not a mechanic
And I am just giving her some things too check that are way cheap before she has to throw money on diagnoses.

Also I will note a timing belt that is going out is NOT a malfunction
They need to be serviced like all belts and if they were replace at the correct mileage you would not experience bent rods or engine parts and most people would get 1,2,3 hundred thousand miles more on there engines

 

Thank you very much Silor and Ryland for the contributions.

Boy that is a lot to consider and think about.

I really appreciate the guidance provided more than you know.

 

Ryland and Silor have good recommendations if it is not a problem with the throttle. What they are stating above I respectfully disagree with. Yes your car has higher mileage, but it is also a 2003. Could you benefit from a tune up (if you haven't had one), yes of course.

I really don't think the timing belt is your problem or your spark plugs or wires. None of these would cause to your car to do what it is doing. Neither would the alternator, you would notice it going out for sure. You would notice when your battery kicks in, and it would be dying frequently, which you didn't mention.

The gas cap would just most likely make your check engine light come on, not really mess with how your car runs. At least that is how it is on chevy's. If the fuel pump was bad, your car wouldn't start to rev up when you were coming to a stop.

If you have someplace around that can check your battery and alternator for free, then go ahead and do it. I really don't think any of the issues mentioned above are your problems though.

Another suggestion that I saw on here was your oxygen sensor. You most likely have 2 of them. They can be a pain to change as well. They do sell a special tool to help with this though. That could be a problem as well though.

Again, no disrespect meant to any of the above posters. Just my .02 cents with the many experiences I've had with multiple cars. I don't trust mechanics one bit.

 

Anytime! just watch out for those tricky mechanics..and always get a second option if you can

 

+1. Second opinions are a must if you can. ;D